<!-- begin SEO -->
{% if site.url %}
  {% assign seo_url = site.url %}
{% endif %}
{% assign seo_url = seo_url | default: site.github.url %}

{% if site.url %}
  {% assign canonical_url = page.url | replace: "index.html", "" | prepend: site.url %}
{% endif %}

<title>{{ site.title }} - Homepage</title>

{% assign seo_description = page.description | default: page.excerpt | default: site.description %}
{% if seo_description %}
  {% assign seo_description = seo_description | markdownify | strip_html | strip_newlines | escape_once %}
{% endif %}

{% assign seo_author = page.author | default: page.author[0] | default: site.author[0] %}
{% if seo_author %}
  {% if seo_author.twitter %}
    {% assign seo_author_twitter = seo_author.twitter %}
  {% else %}
    {% if site.data.authors and site.data.authors[seo_author] %}
      {% assign seo_author_twitter = site.data.authors[seo_author].twitter  %}
    {% else %}
      {% assign seo_author_twitter = seo_author  %}
    {% endif %}
  {% endif %}
  {% assign seo_author_twitter = seo_author_twitter | replace: "@", "" %}
{% endif %}

<meta property="og:locale" content="en">
<meta property="og:site_name" content="{{ site.title }}">
<meta property="og:title" content="{{ site.title }}">

{% if seo_url %}
  <link rel="canonical" href="{{ page.url | prepend: seo_url | replace: "/index.html", "/" }}">
  <meta property="og:url" content="{{ page.url | prepend: seo_url | replace: "/index.html", "/" }}">
{% endif %}

{% if page.excerpt %}
  <meta property="og:description" content="{{ seo_description }}">
{% endif %}

{% if site.twitter.username %}
  <meta name="twitter:site" content="@{{ site.twitter.username | replace: "@", "" }}">
  <meta name="twitter:title" content="{{ page.title | default: site.title | markdownify | strip_html | strip_newlines | escape_once }}">
  <meta name="twitter:description" content="{{ seo_description }}">
  <meta name="twitter:url" content="{{ canonical_url }}">

  {% if seo_author_twitter %}
    <meta name="twitter:creator" content="@{{ seo_author_twitter }}">
  {% endif %}
{% endif %}

{% if site.facebook %}
  {% if site.facebook.publisher %}
    <meta property="article:publisher" content="{{ site.facebook.publisher }}">
  {% endif %}

  {% if site.facebook.app_id %}
    <meta property="fb:app_id" content="{{ site.facebook.app_id }}">
  {% endif %}
{% endif %}

{% if site.google_site_verification %}
  <meta name="google-site-verification" content="{{ site.google_site_verification }}" />
{% endif %}
{% if site.bing_site_verification %}
  <meta name="msvalidate.01" content="{{ site.bing_site_verification }}">
{% endif %}
{% if site.baidu_site_verification %}
  <meta name="baidu-site-verification" content="{{ site.baidu_site_verification }}" />
{% endif %}
<!-- end SEO -->
